A team of researchers from Monash University have now shown that chronic, persistent stress in mice sets off physiological changes that cause cancer cells to move faster and spread to other parts of the body.

The team, led by Dr Erica Sloan and Dr Caroline Le, discovered that adrenaline – a neurotransmitter triggered by stress to increase alertness and rapid reaction to threat – has a downside for animals and people with cancer: it increases the number and size of lymphatic vessels in and around tumours, while also increasing the rate of fluid flow through these vessels. Both of these combine to increase the capacity of lymphatic "highways" to carry and spread tumour cells throughout the body.

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Genevieve Doyle is participating in a study at Peter MacCallum Cancer Centre.Credit:Simon Schluter

"These findings demonstrate an instrumental role for stress ... and suggest that blocking the effects of stress to prevent cancer spread through lymphatic routes may provide a way to improve outcomes for patients with cancer."

The study also reported that a cohort of patients on drugs often used to treat anxiety and high blood pressure (beta blockers that block the actions of adrenaline) were less likely to have secondary cancer that had spread from its primary site.

Dr Sloan said the mice in the study were restrained in a way to make them feel like they would not cope with their circumstances. This was done to mimic the way people feel if they are under significant stress brought on by caring for a sick relative without enough resources, for example. She said it was not designed to mimic an acute and temporary episode of stress such as being chased by a dog.

"What we're talking about is prolonged, ongoing situations where you can't cope," she said.

The mice who were stressed had a much higher rate of their cancer spreading, compared to control mice with cancer who were not put in stressful situations.

Genevieve Doyle, a 56-year-old medical receptionist, is now participating in the Peter MacCallum Cancer Centre study. In January, she was diagnosed with breast cancer after several lumps were detected by BreastScreen.

At the time, she said her stress levels were under control and that she had previously been taking beta blockers to control high blood pressure. She is now hoping these drugs may have offered her some protection while she has treatment for the disease.

"Ever since I started taking them [beta blockers], it has kept me calmer," she said. "I can now go into surgery and not worry about it. I think let's just do this and get it out of the way."

Dr Sloan emphasised that cancer patients should not feel responsible for their own stress because it can be very difficult to control, especially when diagnosed with a serious illness. However, she is hoping the research will lead to new ways of treating cancer in a more holistic way that reduces stress as much as possible along the way. This could be done with drugs like beta blockers, as well as complementary therapies such as meditation or yoga.